Deck Post repair
Well I just learned today that it is "typical" to splice/lap wood in many different ways. Seems as though the way they do it on bridges is exactly the same way for wood in residential construction. Apparently all you need is a 6'' staggered nailing pattern with a 16D nail and you can lap anything, however mathematical analysis must be done for your application. However because I know you are in California, and I don't know how far from the San Andres fault you are , I can assure you that ya won't be able to lap/splice anything , with your header, posts, beams, or otherwise. But with the photo you will supply, it will help determine the appropriate course of action. More then likely you will have to remove the footing, pour a new one, and also have a new full length post, to meet the stringent seismic codes of most of CA. PS. maybe I'm wrong , and you can splice/lap whatever you want no matter how high your deck is. How high is your deck?